The invention relates to a bracket and a system for retaining rigid ducts in a vehicle, applicable to the ducts of an air-conditioning system.
Rigid ducts are typically secured to a vehicle body part or vehicle component using open plastic clips and clamps. The relevant clamp may be provided with a rubber insert that has a compensating effect with respect to relative motion, such as between the clamp, which is fastened to the vehicle body part, and the duct, which is fastened to a vehicle component, thereby absorbing a dynamic load imposed by the running engine. Such clamps are also used to retain the refrigerant ducts of an air conditioning system installed in a vehicle. In the refrigerant circuit of the air conditioning system, a pressurized refrigerant duct is arranged between a condenser and an expansion valve, and a refrigerant suction duct is arranged between the expansion valve and a compressor upstream of the condenser. The compressor is attached to the engine, with the result that engine motions can be transmitted through the compressor via the suction duct and bracket to a vehicle component that is not adversely affected by the engine motion. In addition to the aforementioned motion-damping function, the duct brackets also serve a noise-damping function, since the compressor and the refrigerant flowing in the ducts generate objectionable noises that can be transmitted by the relevant duct to the bracket and thus to the vehicle.
In addition, plastic double clamps are known that can be used to secure parallel ducts.
The object of the invention is to provide improved brackets and systems for supporting rigid ducts in a vehicle that ensure the greatest possible decoupling of the vehicle from the dynamic and acoustic loads of the retained ducts.
According to the invention a bracket for holding a rigid duct includes a mounting part for attachment to a vehicle body part and a duct retaining part connected thereto. The duct retaining part includes a duct receptacle for at least partially surrounding a duct and having spaced inwardly extending clamping projections for providing compressive elastic contact with the duct.
This elastic contact between the receptacle and the duct, which is preferably limited to the clamping projections and by means of which the duct is secured in the receptacle, facilitates the greatest possible decoupling of the retaining parts from the dynamic and acoustic loads placed on the retained duct by the engine and/or the flowing refrigerant, so that the motions of the duct and the noise are not transmitted to the vehicle body.
Preferably, the duct retaining part is designed as a single piece and is made of an elastic material with a low temperature coefficient. In this way, the retention of the duct is also independent of temperature loading and temperature variations that arise during operation of the air conditioning system as a result of the flowing refrigerant and the duct cooled thereby, and also as a result of the engine heat. A well-suited material is the elastic engineering material known as HYTREL, a polyester elastomer made by the DuPont company.
The clamping projections can be axial ribs that can influence the degree of decoupling as a result of their characteristics, e.g. length, thickness, number and material, but especially their number. It has been demonstrated that adequate decoupling can be ensured by coaxial ribs arranged at intervals of 45xc2x0 in the interior of the duct receptacle.
The receptacle can be divided into two portions along its axis and the two portions can be designed such that they are joined together by means of a hinge arranged to pivot parallel to the duct axis so that the duct can be embedded in one part and elastically pressed against the clamping projections by the other part, which pivots parallel to the duct axis onto the duct, thus elastically clamping the duct in the receptacle. To this end, it is possible to provide on both parts latching elements that attach the parts to one another against the clamping resistance.
This embodiment represents a rapid-action coupling with the damping properties in accordance with the object, by means of which assembly time can be reduced.
However, the receptacle can also be designed in the form of an opening having two legs with an open gap between them on the side where the duct is inserted. The duct can, in a simple manner, be pressed through the gap into the receptacle against the clamping force and be retained therein by elastic compression. This embodiment also represents a rapid-action coupling with the damping properties in accordance with the object of the invention. The free ends of the legs can be inwardly tapered to facilitate the pressing-in. This embodimentxe2x80x94like the aforementioned embodimentxe2x80x94simplifies assembly and also disassembly of the retained duct.
The retaining member can advantageously be designed for attachment to the relevant vehicle body part with a mounting screw, wherein at least one recessed oblong hole is made or formed in the mounting part to facilitate compensation for manufacturing tolerances between the parts.
The retaining system for rigid ducts in accordance with the invention is composed of a mounting part and several retaining parts in accordance with the invention arranged thereupon so that they can retain a plurality of ducts, such as the pressurized refrigerant duct and the refrigerant suction duct of an air conditioning system, preferably in parallel orientation. The retaining system is preferably designed as a single piece, which considerably reduces manufacturing and assembly expense.
The retaining system can be designed such that it is able to accommodate a duct with first and second duct sections at an angle to each other. For the latter, it has at least two retaining parts, one of which is provided to engage the angled section of the duct. In order to compensate for manufacturing tolerances, and thus avoid stresses in the retaining system, the retaining member provided for the angled section of the duct is preferably arranged so as to be movable, perpendicular to the axis of its duct receptacle, in the plane defined by the first and second duct sections. A slide rail may be provided on the mounting part perpendicular to the axis of the duct receptacle.
This retaining system is preferably made of a plastic with a low temperature coefficient, more particularly the elastic engineering material HYTREL from the DuPont company, so that the object according to the invention of decoupling the vehicle from the dynamic and acoustic loads is ensured for each of the retained ducts. The system can be designed in one piece with the exception of the previously described moveable duct retaining member.
The low temperature coefficient of the aforementioned material ensures that the dynamic and acoustic decoupling occurs even at very different duct and engine compartment temperatures.
The retaining system represents a compact mount for a plurality of ducts, which simplifies installation and disassembly of the ducts. A one-piece design, in particular, is associated with reduced cost and weight while also contributing to assembly process reliability.
The invention is explained below with the aid of exemplary embodiments.